Nylon-11 is an engineering resin used in various engineering plastics. Along with excellent dimensional stability, Nylon-11 exhibits excellent abrasion and vibration resistance. The Nylon-11 is used in electrical applications, e.g., cable extrusion, mechanical applications, e.g., to mold intricate components, and in the manufacture of sports equipment, industrial fabrics, powder coatings and synthetic fibers.
Presently, Castor oil is the precursor of 11-aminoundecanoic acid, the Nylon-11 monomer. However, the synthesis of Nylon-11 from Castor oil involves at least six reaction steps, including an energy intensive pyrolysis (450.degree.-500.degree. C.) reaction. In the present invention, 11-aminoundecanoic acid was produced through the intermediacy of 11-carbamoylundecanoic acid. There have been two reported syntheses of 11-carbamoylundecanoic acid. In U.K. Patent No. 1,283,796, 1,1'-peroxydicyclohexylamine was thermally decomposed below 450.degree. C. to give decane-1,10-dicarbonimide, which was subsequently hydrolyzed to obtain the amide. Similarly, Kataoka and Ohno reported the synthesis of 11-carbamoylundecanoic acid from a cyclic-hydroxyimino ketone by treatment with concentrated sulfuric acid.
According to the present invention, Nylon-11 monomer is synthesized from 12-oxododecanoic acid oxime via the intermediacy of 11-carbamoylundecanoic acid and 11-(methoxycarbonylamino)undecanoic acid. U.S. Pat. Application Serial No. 08/065,333, provides for the synthesis of 12-oxododecanoic acid oxime from the seed oil of Vernonia galamensis, an annual herb, indigenous to tropical and sub-tropical Africa. The present invention provides a synthetic scheme in which one carbon atom is removed from the carbon backbone of the 12-oxododecanoic acid oxime. In the synthetic scheme of the present invention, the oxime is isomerized via Beckmann rearrangement to the amide (11-carbamoylundecanoic acid), which then undergoes Hofmann degradation and hydrolysis to give 11-aminoundecanoic acid.